A Morphological Integration Perspective on the Evolution of Dimorphism among Sexes and Social Insect Castes
A Morphological Integration Perspective on the Evolution of Dimorphism among Sexes and Social Insect Castes
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DOI：
10.1093/icb/icz053
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发表时间：
2019-08-01
影响因子：
2.6
通讯作者：
Economo, Evan P.
中科院分区：
文献类型：
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作者：
Friedman, Nicholas R.;Remes, Vladimir;Economo, Evan P.
许多物种已经进化出了交替的表型，从而使个体能够有条件地产生有利于繁殖成功的表型。这种现象的例子包括两性二态性、替代性生殖策略和社会性昆虫种姓。虽然二态表型的进化功能和发育机制已经得到了广泛的研究，但对各表型之间的进化协方差研究却很少。我们扩展形态整合的概念框架和方法，假设二态性状倾向于在性别或社会种姓之间较少整合。在群居昆虫的情况下，我们描述了我们最近对蚁属的研究结果，其中工蚁有主要和次要的工蚁种姓，它们在巢内和周围执行不同的行为表。以鸟类为例，我们描述了一种对鸣禽家族的新分析，这种鸟类的羽毛颜色在雄性和雌性之间差异很大，每种性别都有明显的独立变化。蚁头形状在每个工种中都是高度专门化的，在工种之间的融合程度较弱，而胸形状在工种之间的融合程度较强。同样，在鸟类中，我们发现二态性与两性之间的整合程度呈负相关。我们还发现，小鹪鹩（Malurus）的许多羽毛斑块进化出更大的二色性，整合性下降。总之，这表明进化过程中增加的二态性导致性别和社会种姓之间整合的减少。我们推测，一旦一种二态性机制进化，这种机制可以在一个性别或种姓中产生独立的变异，选择可能会对其起作用。
Many species have evolved alternate phenotypes, thus enabling individuals to conditionally produce phenotypes that are favorable for reproductive success. Examples of this phenomenon include sexual dimorphism, alternative reproductive strategies, and social insect castes. While the evolutionary functions and developmental mechanisms of dimorphic phenotypes have been studied extensively, little attention has focused on the evolutionary covariance between each phenotype. We extend the conceptual framework and methods of morphological integration to hypothesize that dimorphic traits tend to be less integrated between sexes or social castes. In the case of social insects, we describe results from our recent study of an ant genus in which workers have major and minor worker castes that perform different behavioral repertoires in and around the nest. In the case of birds, we describe a new analysis of a family of songbirds that exhibits plumage coloration that can differ greatly between males and females, with apparently independent changes in each sex. Ant head shape, which is highly specialized in each worker caste, was weakly integrated between worker castes, whereas thorax shape, which is more monomorphic, was tightly integrated. Similarly, in birds, we found a negative association between dimorphism and the degree of integration between sexes. We also found that integration decreased in fairy wrens (Malurus) for many feather patches that evolved greater dichromatism. Together, this suggests that the process of evolving increased dimorphism results in a decrease in integration between sexes and social castes. We speculate that once a mechanism for dimorphism evolves, that mechanism can create independent variation in one sex or caste upon which selection may act.